Portable pressure sprayers with self-contained pressurizing pump means are well known in the art. However, previously all these known sprayers had one or more of the following disadvantages, namely: the liquids dispensed corroded their metal parts, it took too long to pressurize their containers, the containers were relatively heavy to carry, their caps and/or containers cracked or leaked under pressure, they were too complicated and expensive having too many parts, they were difficult to repair and/or assemble, and they were not easily adapted for other uses or applications.